Railway traffic controlling apparatus



June 16, 1931. H. A.YWALLACE 'RAILWAY TRAFFIC CONTROLLING APPARATUSOriginal Filed May 5, 1926 10 Sheets-Sheet l INVENTORI H- Q lb MW a z WJune 16, 1931. H. A. WALLACE RAILWAY TRAFFIC CONTROLLING APARATUS l0Sheets-Sheet 2 INVENTQR Original Filed May 5, 1926 I H. A. WALLACEILWAY'TRAFFIG CONTROLLING APPARATUS Jun 16, 1931 Original Filed May 5,1926 10 Sheets-Sheet 3 INVENTOR I June 16,- 1931. H. A. WALLACE RAILWAYTRAFFIC CONTROLLING APPARATUS Original Filed May 5, 1926 10 Sheets-Sheet4 .RZMM O I & W w m Ma Q v .A v. mm l RN H QNNUINN r! NN BMW, \MMJQ June16,- 1931. H. A. wALLAcE' RAILWAY TRAFFIC CONTROLLING APPARATUS OriginalFiled May sj 1926 10 Sheet s-Sheet 5 INVENTOR 1 ,4, Q WMM June 16, 1931.H. A. WALLACE RAILWAY TRAFFIC CONTROLLING APPARATUS ori inal Filed May5, 1926 10 Sheets-Sheet 6 lNvENTOR i "Haw/ aw 3 mw NW E mw I. DmvhB fimwNW\EL 9g WWWML mg June 16, 1931. H. A. WALLACE RAILWAY TRAFFICCONTROLLING APPARATUS Original Filed May 5, 1926 1o Sheets-Sheet 7-INVENTORL AAa/m M June 16, 1931. H. A. W ALLACE RAILWAY TRAFFICCONTROLLING APPARATUS ox iginal Filed May 5, .1926 10 Sheets-Sheet aLEI-4Q June 16, 1931.

H. A. WALLACE RAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed May5, 1926 lOSheets-Sfieet 9 INVENTORi M.Q.WWM@M' June 16, 1931. A. WALLACERAILWAY TRAFFIC CONTROLLING APPARATUS Original Filed May 5, 1926 10Sheets-Sheet 10 INVENTORZ Mar/04b l HERBERT A. WALLACE, or EDGEWOODBOROUGH, PENNSYLVANIA, ASSIGNOR TO UNION swrrorr & SIGNAL COMPANY, orSWISSVALLE, PENNSYLVANIA, A CORPORA- [DION OF PENNSYLVANIA P OF! RAILWAYTRAFFIC CONTROLLING APPARATUS Application filed May 5, 1926, Seria1 No.'106,871. Renewed August 3, 1929;

My invention relates to railway traflic con-' trolling apparatus, andparticularly to apackway portion of such apparatus. I purpose of myinvention is the provielon of novel means for supplying energy to T thetrack rails so that uninterrupted alterrails but that under certainconditions the supply of such current is periodically interrupted, thecharacteristic of these periodic interruptions being controlled inaccordance with trafiic conditions.

I will describe several forins'of trackw'ay l apparatus embodying myinvention, and will then point out the novel featuresthe claims.

In the accompanying drawings, Figs. 1 to 8, inclusive, are diagrammaticviews illustrating several forms of trackway apparatus embodying myinvention as applied to a stretch of track over which traffic normally Jmoms in one direction only. Fig. 9 is a View owing my invention appliedto two paralitel tracks connected by cross-overs. Fig. 10

l is a view illustrating the application of my invention to a stretchoftrack over' which traiii'c moves in both directions. i

v Similar reference characters refer to simi- 'lar parts in each of theseveral views.

The specific modifications shown in Figs. 6, 9 and 10 have been made thesubject-matter of separate divisional applications desig nated by SerialNumbers 383,73l,'383,732,and

383,733, respectively, and all filed on August intermediate position,nating current is normally supplied to the reof in constantly connectedacross the railsadja'cent the entrance end of the associated sectionjandwinding 7 is constantly supplied withaltee nating current from terminalsand Z) of a suitable source of alternating current not shown in thedrawing. Each relay R also comprises two contactslQ and 17 arranged tooccupy a right-hand a left-hand or an depending upon the relativepolarity of the alternating current fuppliedto the windings 6 and 7 ofthe re= Eachtrack sectionis supplied with alter nating current from atrack transformerdesignated by the reference character T withan exponentcorresponding to the location and comprising a secondary 3 constantlyconnected across the rails adjacent the exit end of the associatedsection in series with the usual impedance 5. The supply of alternatingcurrent to the primary 4 of each track transformer T is controlled by arepeater relay designated by the reference character P with an exponentcorresponding to the location and controlled by the adjacent track relayR. Referring, for example, to repeater relay P it will be seen that whenrelay R is energized in either direction so that contact 12 1s swung toeither extreme position, current flows from one terminal a of a suitablesource of current, through contact 12 of relay thence back tothe otherterminal 6 of the same source. When relay B is de-energized, however,this circuit for relay P is open and the relay becomes de-energized.

Each track section is further provided with a coding relay designated bythe reference character K with an appropriate distinguishing exponentand controlled by the repeater relay for the section nextin rear. Eachrelay K comprisestwo magnets 8 and 9 and a pivoted armature 49 biased toa central position but arranged to be attracted by one or the other ofthe magnets. Carried by the armature 49are movable contacts lland l4which swing to one side or the other dependingupon which of the magnets8 or 9 is attracting the armature. The relays K are intended to ope'rateon direct current, and since the source R and wire 13 to the windingofrelay P and of energy, the terminals a and Z; of which are shown in thedrawing, is a source of alternating current a rectifier is included inthe circuit for each relay K to change the alternating current suppliedthereto to a direct current.

Referring particularly to coding relay K the circuit for this relay maybe traced from terminal a, through wire 25, back contact 26 of repeaterrelay P wi e 27,rcctifier10, magnets 8 and 9 of relay K and wire 28 toterminal b. It will be seen that contact 1111 is arranged to shortcircuit magnet 9 and contact 11.11 is arranged to short circuit magnet8. The contacts are so arranged that when the coding relay isdeenergized contact li -11 is closed: If therefore, the operatingcircuit just traced for the relay K is closed, current supplied to therelay flows through magnet 8, but is shunted around magnet 9 by contact11-11. Armature 49 is therefore attracted by magnet 8 to open contact1l11 and close contact 1111". Current is then supplied to magnet 9 andmagnet 8 is short circuited. The magnets 8 and 9 are arranged to be slowacting however, so that an interval of time elapses before the mcreasmgflux 1n magnet 9 overcomes the decreasing flux in magnet 8 to asufiicientdegree to again reverse armature 49. At theexpiration of thistime interval armature l9 swings back toward magnet 9 and contact 1111is opened and contact 11-l1 is closed. Another time interval elapsesbefore :armature349 is again reversed. It follows that as long as thecircuit is closed for relay K, the armature 49 oscillates so that thecontacts controlled by the armature are operated intermittently. Thecontacts 14--1l and 14 14 are so adjusted that these-contacts are bothclosed when the relay is de-energized. Then the relay is energizedhowever, these contacts are opened alternately. The parts are soarranged as indicated by the unequal shunting-bands on the magnets 8 and9, that when the relay K is operated contact 1414t is closed for alargerproportion of each cycle than is contact 1414". For example, assumingthat a com plete cycle of operation of the relay requires one second.the contacts may be so arranged that contact 1l14" is closed fortwo-thirds of asecond and contact 1t14 is closed for one-third of asecond. This adjustment to accomplish unequal timing of the relaycontacts or ,limping of, therelay. may be effected by suitableadjustments inthe structure .ofthe relay or in the positions of thecontact members.

The supply of current to the primary 4 I of each, tracktransformer. T iscontrolled. by

theadjacent repeater relayzP as stated here inbefore, and. also bytheadjacent coding relay K. Transforn'ier T for example, is providedWithv onecircuit which may .be traced from terminal a throu h wire 15contact 14l-14 of coding relay K wire 16, contact 17--17 o-r 17-17" ofrelay R wire 18, front contact 19 of relay P wire 20, primary 4 oftransformer T wire 21, front contact 22 of relay P and wire 23to'terminal b. This circuit is closed only when track relay B isenergized in one direction or the other, and when relay P is energizedand when coding relay K is de-energized 'or is energized in suchdirection as to swing contact 14 to the right. It follows that if thecircuit just traced for transformer T is closed and re lay K isoperati'ngas when a train occupies section AB, the oscillation ofcontact 14 will periodically interrupt such. circuit. Contactl414-. isclosed for two-thirds of a sec ond and open for one-third of a secondduring each cycle of operation of relay K so that current will besupplied to the track rails under these conditions in the form of codeimpulse combinations, comprising impulses of alternating current oftwo-thirds of a second duration separated by time intervals of one-thirdof a second during which no current flows in the trackway. Code impulsecombinations supplied to the t'ackway in this manner I shall hereinafterterm the proceed code.

If relay P is de-energized, as by the presence of a train in section BC,current flows from terminal a, through wire 15, contact 14-14 of codingrelay K wire 24-, back contact 22 of relay P wire 21, primary 4 oftransformer T wire back contact 19 of relay P and wire 23 to terminalZ). lVhen this circuit is closed and relay K becomes energized theintermittent operation of contact 14.-1 l"' periodically interrupts'thecurrent supplied to the rails of section A-B so that the rails are thensupplied with c rrent in the form of code impulse combinations.comprising impulses of alternating current of one-third of a secondduration separated by time intervals of two-thirds of a second duringwhich time no current flows in the trackway. Code impulse combinationssunplied in this manner I shall hereinafter call the caution code.

It should be pointed out that when relay P is energized current of onerelativepolarity which I will call normal relative polarity is suppliedto the rails of section AB but that when relay P becomes ale-energizedcurrent of the opposite relative polaritv which I will call. reverserelative Polai'itv ative polarity, these contacts are swung .to the leftinto their reverse positions. 1

The track relays may be used to control trackway signals or othergoverning means,

not shown in the drawing, in any suitable .ative polarity is thereforesupplied to the rails of section 13-43 by transformer T so that relay Bis energized in the reverse direction. Relay P is therefore energizedand the back contact 26 of this relay being open, relay K isde-energized. The current supplied to primary 4 of transformer T istherefore uninterrupted. In similar fashion the current of normalrelative polarity which is supplied to the rails of section A-B picks uprelay R in the normal direction so that relay P is'energized thereby.holding open the circuit for relay K so that the current supplied totherails of section AB is uninterrupted. In similar manner,uninterrupted current or normal relative polarity is supplied to therails of the section to the left of point A.

It should be pointed out that the trackway apparatus'here shown anddescribed is suitable for, though in no way limited to, use inconnection with train carried governing .means formin no art of m resentinvention and omitted from the drawing for the sake of simplicity. YForpresent purposes it is suflicient to state that when the portion oftrack occupied by the train is supplied with code impulsecombinations'iii accordance with the proceed'code, a proceed indicationis received on boardthe train; when the portion of track which isoccupied by the train is supplied with code impulse combinations inaccordance with the caution code, a caution indication is received onboard the train; and when the rails occupied by the train are suppliedwith uninterrupted alternatingcurrent or with no current, the trainreceives a stop indication. In train control systems of the typedescribed, the receiving apparatus through the medium of which the traincarried governing means is controlled in accordance with thetrackwaycurrent is usuallylocated at the forward end of the train inadvance of the front aXle. With this arrangement it is apparent thattrain controlling current must be supplied to the train from a point inadvance of. the train.

'With this explanation in mind, I will as some that a train movingin thedirection in- .dicated by the, arrowl passes through the stretch oftrack shown in the drawing. As this train enters section A;B,' relay Bbecomes de-energized, thereby de-energizing relay P and completing thecircuit for coding in accordance with the caution code. trainthereforereceives a caution llldlOittlOl'l' relay K so that the latter relaycommences to operate. The current supplied to section A.-B is thereforebroken u into code im- 1 p pulse combinations in accordance with theproceed code so that a proceed indication is received onboard the trainthroughout section A-B.

When the train enters section 13-6, the resulting de-energization ofrelays R and P completes the circuit for coding relay K which thereforecommences to operate and the intermittent operation of contact 1t14J ofrelay K breaks up the current supplied to section 15-0 into code impulsecombinations The track relay for the section next in rear swings fromitsreverse to its normal position. Referring to the drawing, relay B isenergized in the reverse direction because relay P is de-energized dueto theipresence of the train Vin the section to the right of point C.When this train leaves the section it now occupies, relay R will becomeenergized,

picking up relay P and energizing relay B in the normal direction.During this operation of relay R the circuit for relay P will be openfor a brief interval, but due to the slow releasing characteristics ofrelay P this relay will hold its front contact closed, therebypreventing a momentary reversal in the polarity of the current suppliedto section A-B. For similar reasons each of the other relays P is madeslow releasing.

Referring now to Fig. 2, the apparatus is similar to that shown in Fig.1, but when one of the relays P is tie-energized, alternating current issupplied without interruption to the primary 4 of the adjacenttransformer Tover back contacts 22 and 19 of the repeater vrelay P.

Each track section is also provided, in Fig. 2, with an auxiliarytransformer designated by the reference character Q and comprising aprimary 29 connected across the rails at an intermediate point in thesection. The secondary 30 of each transformer Q, is arranged to be attimes periodically short-circuited. Referring, for example, to trans-When a coding relay K is transmitting the caution code to the trackway,therefore, each time contact 33-33 closes, the secondary 30 ofthe-auxiliary transformer Q for that section is short circuited so thatsubstantially no current flows in the rails between the point ofconnection of the auxiliary transformer Q, and the entrance end of thesection during this interval of short circuit. As shown in the drawing atrain V occupies the section to the right of point C and the parts ofthe apparatus occupy the same positions as have already been describedin connection with Fig. 1.

I will now assume that a train moves through the stretch of track shownin the drawing in the direction indicated by the arrow. WVhen this trainenters section A-B relay K commences to operate due to the opening ofrelays R and P and current is therefore supplied to the rails of sectionA-B in accordance with the proceed code as explained in connection withFig. 1 so thatthe train receives a proceed indication. When the trainenters section B-C the coding relay K commences to operate but relay Pis 'de-energized so that transformer T supplies uninterruptedalternating current to the rails of section BQ. But each operation ofcontact 33-'33" of relay K short circuits the secondary 300f transformerQ so that the transformer periodically shunts the rails and the currentin that portion of the section between B and Q is interrupted inaccordance with the caution code. As the train proceeds through sectionBC, then, a cantion indication is received on board the train between Band Q but a stop indication is received onboard the train between Q andpoint C.

Referring now to Fig. 3, the track transformer T for each section islocated at the entrance end of each section and the primary 4 of thistransformer is constantly supplied with alternating current fromterminals a and b so that the track section is at all times suppliedwith alternating current from a point adjacent its entrance end.lVinding 6 of each. track relay is connected across the rails adjacentthe exit end of the section. Interrupted current is at times supplied toeach section from a point adjacent its exit end from a train controllingtransformer desig nated by the reference character I. with an exponentcorresponding to the location and having its secondary 35 connectedacross the rails adjacent the exit end of the section through the'usualimpedance 37. 1

Located adjacent the entrance end of each section is a line relaydesignated by the reference character D with an appropriatedistinguishing exponent. Each line relay D comprises two windings 6 and7, one of which, 7, is constantly supplied with alternating current fromterminals or and 6. Referring particularly to relay D ,win'ding '6o'fthis relay R wire 41, winding 6 of relay D wire 42, front contact 22 ofrelay P and wire 23 to terminal 5. When this circuit is closed, currentof normal relative polarity is supplied to relay D and the relay isenergized in such direction that contacts 12 and 17 swing to the right.When relay P is deenergized, however, current flows from terminal a,through back contact 22 of relay P wire 42, winding 6 of relay D wire41, front contact 40 of relay R wire 39, back contact 19 of relay P andwire 23 to terminal I). lVhen this circuit is closed, current of reverserelative polarity is supplied to winding 6 of relay D, so that contacts12 and 17 are swung to their left-hand, or reverse positions. T hecontrol of each relay P by the adjacent relay 1) is similar to thecontrol of the relays P by the associated relays R in Figs. 1 and 2, andwill be readily understood from the drawing. The circuit for primary 36of each transformer L is controlled by the adjacent code relay K,through contacts 1'4-14 and 14-14", which contacts are normally open butare arranged to close alternately when the relay is operated sothat'contact 1414 5' is closed for substantially two-thirds of a secondand contact 14.14 is closed for substantially one-third of a second. Onecircuit for primary 36 of transformer L for ex ample, may be traced fromterminal a, .1.:-'

through contact 1414 of relay K wire 43, front contact 44 of relay Pwire 45, and primary 36 of transformer L to terminal Z). This circuit isclosed when relay P is energi'zed, that is, when relay D is energized'inone direction or the other. When relay P is de-energized, a circuit isclosed from terminal a, through contact 1414 of relayK wire 47, backcontact 44 of relay P wire 45, and primary 36 of transformer L 'toterminal b. It follows that when relay K is being operated, the rails'of section A-B are supplied from transformer L with code impulsecombinations according to the proceed code orthe caution so'd'edepending upon whether 'rela- P -is energized or de-ener 'ize'd. k.) D

As shown in the drawings, the section to the rlght of pointC is occupledby atrain V, so that the track relay forthis section (not shown in thedrawings) is de-en'ergized, caus- I.

ing relay D to be 'de-energized. Relay P is'therefore open sothatcurrent of' r'everse relative fpolarity'is supplied to winding 6 of linerelay 'D energizing this relay in the reversed direction. Relay P istherefore energiz'ed and current of normal relative polarity is suppliedto winding 6 of relay D picking up this relay in the normal direction.Relays R and R are energized by current supplied "t-o-theass'ociate'dsection from" track transformers T located adjacent the entrance ends ofthe sections. Relays K in the sections illustrated are all de-energizedand no current is supplied to the corresponding transformers L.

I will now assume that a train moving in the direction of the arrowmoves through the stretch of track shown in the drawings. As this trainenters section A-B, relay R becomes de-energized. The closing of backcontact 34: of relay R closes the circuit for coding relay K so that thecontacts controlled by this relay commence to operate. Relay P as hasalready been explained, is energized so that each time contact l l-l4 ofrelay 1' is closed an impulse of alternating current is supplied toprimary 36 of transformer L and therefore to the rails of section Al l.It follows that under these conditions the train receives a'code impulsecombination in accordance with the proceed code. When the train enterssection BC, relay R becomes de-energized, thereby closing, at backcontact 3st, the operating circuit for the codin relay K Relay P isde-en ergized due to the presence of the train V in section to the rightof point C so that each time contact 14-44 of coding relay K becomesclosed an impulse of alternating current is supplied to the rils .ofsection B-C and the train is therefore supplied with code impulsecombinations in accordance with the caution code.

Nhen the train moves out of a section, the track relay R for thatsection becomes energized during the next time interval between impulsesfrom transformer L, by current from the associated transformer T,thereby opening back contact 34- and de-energizing the coding relay Kfor that section.

Two-element relays of the type illustrated for the track relays R,usually operate in such. manner that the relay picks up when currents ofone relative polarity are supplied to the windings of the relay. Whenthe polarity of either of such currents is reversed, the relay will notpick up, but will hold its front contacts open.

The parts are so arranged that current from a transformer L is of suchrelative polarity. as to hold open the front contacts of the associatedtrack relay, and the relay can not, therefore, be improperly energizeddue to current from the transformer L when the section is occupied.

Referring now to Fig. 4c, the traclrway ap-' paratus illustrated in thisview is similar to that just described in connection with Fig. 8, exceptthat the caution code .is transmitted to the trackway at an intermediatepoint in the section by a transformer Q. In Fig. 4, referring forexample, to section AB, when relay P is energized and relay K is beingoperated, current is supplied to transformer L over front contact 44- ofrelay P and conback contact d8 of relay P tact lk-ll of relay K Underthese conditions the rails of section A.B are supplied with currentaccording to the proceed code. When relay P is de-energized however, thecircuit for transformer L is opened and current is supplied to primary30 of transformer Q over contact 33 -33 of relay K and The rails ofsection A-B are then supplied with the caution code from transformer QAs shown in the drawing the section to the right of point C is occupiedby train V and the condition of the apparatus will be readily understoodfrom the explanation of Fig. 3. When a train moving in the direction ofthe arrow passes through the stretch of track shown in the drawings theoperation of the apparatus located at point B is the same as in Fig. 3-and the train receives a. proceed indication throughout section AB. Whenthis train enters section BC, relay R becomes de-energized, therebycompleting the circuit for coding relay K at back contact 34: of thisrelay and setting the coding relay into operation. Relay P isde-energiZed due to the presence of a train V in the section to theright of point C so that the supply of current to transform er L isinterrupted at front contact 44 ofrelay P Back contact idof relay P isclosed so that each time contact 33 swings to the left so that contact3333" is closed an impulse of energy is supplied to the secondary 30 oftransformer Q It follows that the train will be supplied with thecaution code between the entrance end of section B-C and transformer QP.When the train is between transformer QP and point C, it is deprived ofalternating current from the trackway due to the shunting effect of thewheels and axles of the train and the train receives a stop indication.

Under some conditions of operation it may be desirable to'divide a tracksection by means of insulated joints 2 into two or more sub sections. InFig. 5, for example, section BC is divided into a forward sub-section XCand a rear sub-section BX. Wind ing 6 of track relay R is connectedacross the rails adjacent the entrance end of the section to the rightof point C and secondary 35 of transformer L is connected across therails adjacent the exit end of section BC..

Two track relays R and R similar to relay B have their windings 6connected across the rails on opposite sides of point X and thetransformer L has its secondary 35 connect-' ed across the railsadjacent the exit end of sub-section B-X. Alternating current isconstantly supplied to sub-section BX adjacent the entrance end of thissub-section by transformer T. A line relay D located at point B iscontrolled by the track relays R R and R and by the repeater relay P sothat if relays R R and R are energized this line relay is supplied withcurrent of one relcontact 19 of relay P wire 50, front contact 51 ofrelay R wire 52, front contact 53 of relay R wire 54, winding 6 of relayD wire 55, front contact 22 of relay P and wire 23 to terminal I). Whenthis circuit is closed,

current of normal relative polarity is supplied to winding 6 of relay Dand the normal contacts of this relay are closed. Under these conditionsrelay P is energized and current of normal relative polarity is suppliedto the rails of the section to the left of point B through transformer Las explained in connection with Fig. 1. lVhen relay P is (lo-energizedcurrent flows from terminal a, through bac-l: contact 22 of relay P Wire55, winding 6 of relay D wire 5 f, front con tact 53 of relay R wire 52,front contact 51 of relay R wire 50, back contact 19 of relay P and wire23 to terminal Z). hen this circuit is closed, current of reverserelative polarity is supplied to winding 6 of relay D so that thereverse contacts of the relay are closed. \Vhen relay D is ole-energizedas by the presence of a train in section BC, relay P becomesde-energized and current of reverse polarity is supplied to the rails ofthe section to the left of point B. A coding relay K is located at pointB and is controlled as shown in Fig. 1 so that this relay operates, whenthe section to the left of point B is occupied, to interrupt the currentsupplied to the rails of such section in accordance with the caution orpro eed code depending upon the condition of relay P It will be plainthat the control of the apparatus for the section to the left of point Bis similar to the control of the corresponding apparatus in Fig. 1except that relay D is substituted for relay R in the control of thisapparatus.

A coding relay K is provided with a circuit including back contact 5'?of relay B so that this relay operates when section XC is occupied. Insimiiar manner coding relay K is controlled by back contact 56 of relayR so that this relay O] 3012-.S when sub-section B-X occupied. Relay Kis controlled as in Fig. 3 to interrupt the current supplied to primary36 of transformer L in accordance ith the proceed or caution codeaccording relay P is energized or deenergized. The relay K inconyunction with relay P controls the supply of current to transformer LThus, when relay P is energized, current flows fron terminal a. throughfront contact 58 of relay P wire 59, contact ll l of relay K wire 60,front contact 61 of relay R wire 62, primary 36 of transformer If andwire 63 to terminal Z). W'hen relay P is de-energized however, currentflows from terminal a, through back con tact 58 of relay P wire 64,contact l t-14 of relay K wire 60, front contact 61 of relay R wire 62,primary 86 of transformer L and wire 63 to terminal 6. It is manifesttherefore that when relay is energized and when relay K is operated,sub-section BX is supplied with the proceed code if re lay P isenergized but that sub-section BX is supplied with the caution code ifrelay P is ole-energized.

As shown in the drawing the stretch of track is unoccupied and relay Ris energized in the normal direction. Relay P is therefore energized.Current is supplied to the primary of transformer L over front con tact4A of relay P so that relay R is ener gized, and back contact 57 isopen. Relay K is therefore de -energized. Current is constantly suppliedto sub-section BX from transformer T energizing relay R so that thecircuit for coding relay K is open at back contact 56 of relay R Relay Dis therefore energized in the normal direction and relay P is energizedso that current of normal relative polarity is supplied to the sectionto the left of point B. If a train moving in the direction of the arrowenters section B-X, the resulting de-energization of relay R sets codingrelay K into operation. Relays P and R remain energized so that theoperation of relay K supplies current to primary 36 of transformer L inaccordance with the proceed code. If relay P were lo-energized, as bythe presence of a train in the section to the ri 'ht of point C, thecircuit for primary 36 of transformer L would include contact l4;1 l ofrelay K so that sub-section B-X would then be supplied in accordancewith the caution code.

Returning to the assumption that relay P is energized, when the trainenters sub-section XC, relay l 2 becomes Clo-energized, setting relay Kinto operation. Current is therefore supplied to the rails of thesub-section -C through transformer L in accordance with the proceedcode. if relay P were de-energized the current supplied to the rails ofthe sub-section would be interrup ed in accordance with the cautioncode.

It will be seen therefore that when relay P is energized a trainproceeding through the subsection BX is supplied with current accordingto the proceed code from transformer and when proceeding through thesub-section X@ is supplied with current according to the proceed codefrom transformer L Va li-en relay P is do energized, however, the trainin section BX receives current according to the caution code froi 1transformer L and when in sub-section X-C receives current according tothe cau tion code from transformer L In the modification illustrated inFig. 6, each section is provided with a track relay R, a repeater relayP, and a coding relay K controlled in the same manner as explained inlio connection with Fig. 1. Current supplied to the rails of the sectionfrom a transformer L located adjacent the exit end of the section.Current-is at times supplied to primary 36 of each transformer L fromone or the other of two sources of alternating current of differentfrequencies. For this purpose each section is provided with twotransformers designated by the reference characters 0 and S,respectively, with exponents corresponding to the location. The primary68 of each transformer 0 is constantly supplied with alternating currentof one frequency from an alternator M, over a transmission line 81. Thetrain carried apparatus is arranged to respond only to current of thisfrequency in the track rails. For other purposes such as theenergization of the track relays and the line circuits current issupplied from a second alternator N at a different frequency to theprimary 70 of each transformer S over transmission line 82. Although anysuitable frequencies may be chosen for alternators M and N, for purposesof explanation I will assume that the freuency of the current suppliedby alternator M is 100 cycles per second and that the frequency of thecurrent supplied by alternator N is60 cycles per second. As shown in thedrawing the section to the right of point C is occupied by train V.Relays'R and P are therefore de-energized, and (SO-cycle current ofreverse relative polarity is therefore supplied from transformer S toprimary 36 of transformer L over contact 14i14lof re lay K and backcontacts 22 and 19 of relay P Relay R is therefore energized in thereverse direction and relay P is picked up. 6()cycle current of normalrelative polarity is therefore supplied to primary36 of transformer Lfrom transformer S over contact l4j+lt of relay K contacts 16 and 17 ofrelay R and front contacts 19 and 22 of relay P so that relay R ispicked up in the normal direction and relay P is also energized. T willnow assume that a train moving in the direction of the arrow passesthrough the stretch of track shown in the drawing. When this trainenters section AB, the resulting de-energization of relay P energizescoding relay K Each time contact 3333 of relay K? is closed, a surge of100-cycle current flows from secondary 6 7 of transformer O through wire71, contact 33-33 of relay K wire 72, front contact of relay P wires 73and 74:, primary 36 of transformer L and wires 75,76 and .77, back tosecondary 67 of transformer 03.. f hen this circuit is closed, contact 1l14lis open so that the supply of 60-cycle current to transformer L isinterrupted. When the contacts of relay K swing tothe left the circuitjust traced for secondary 67 of transformer 0 is open and the circuitisreestablished for the supply of 60- cycle current from secondary 69 oftransformer S to primary 36 of transformer L It."follows, therefore,that section A B is supplied with'100-cyc1e current in the form ofimpulses of energy of two-thirds of a sec- 0nd duration separated bytime intervals of onethird of a second and that during each in- A tervalof oneethird of a second,'60-cycle current the latter beinginterruptedin accordr ance with the proceed code .to give a proceed indication onthe train.

When the trainenters section BC relay K commences to operate. Each timethe contacts of this relay swing to the left contact 1 11 1 opens,thereby interrupting the circuit over which (SO-cycle current issupplied to primary 36 of transformer L At the same time however contact33--33 of relay K closes and 100-cycle current flows from secondary 6?of transformer O through wire 71, contact 3"-33 of relay K wire 78, backcontact 66 of relay P wire 79, primary 30 of transformer Q and wires and77 back to secondary 67 of transformer O Under these conditions,therefore, -cycle current is supplied to section B.C at the point ofconnection of transformer Q in the form of impulses each of one-third ofa second duration separated by time intervals of two thirds' of a secondduration, during which intervals 60-cycle current is supplied to therails of the section at transformer L. lit follows that between point Band the point of connection of transformer Q the rails are supplied withalternateimpulses of 100- cycl'eand 60-cyc1e currents of which the 100'-cycle current is interrupted in accordance with the caution code, butthat between the point of connection of transformer O and pointC, therails are supplied with interrupted 60-cycle current but with no100-cycle current. The train therefore receives a caution indicationbetween point B and the trans former QF, and a stop indication betweentransformer Q and point C. After the train has passed out of section AB,the next impulse of 60-cycle current picks up relay R which in turnpicks up relay P thereby dellO energizing relay With relay KBdeenrgized, uninterrupted (SO-cycle current is supplied to the rails ofsection AB as will be plain from the drawings. The operation of theapparatus as the train passes out of section BC will be readilyunderstood from 1 the foregoing.

In the modification illustrated a Fig. 7,

BO-cycle current is constantly supplied to the rails of each sectionfrom transformer T,"located adjacent the entrance end of the explanationof that view. lOO-cycle current is at times supplied to the rails ofeach section by means of a transformer Llocated adjacent the exit end ofthe section. Referring for example to section AB, if this section wereoccupied by a train so that relay R were deenergized to complete thecircuit for relay K l00-cycle current would be supplied to primary 3 6of transformer L each time con tact 33 swung to the right. Under theseconditions the rails of section AB would be supplied with 100-cyclecurrent interrupted in accordance with he proceed codej Similarly, Iwill assume that section BC is occupied by a' trainso that relay K isoperated. Under these conditions 100-cycle current is supplied overcontact 3333 of relay K and back contact of relay P to primary 36 oftransformer L each time the contacts of coding relay K swing to theleft. Under these conditions therefore the rails of section BCaresupplied with 100- cycle current periodically interrupted in accordance with the caution code;

The trackway circuits shown in Fig, 8 ar similar to those just describedin Fig. 7 except that when a repeater relay P is de-energized and thecorresponding coding relay is energized, lOO-cycle current is suppliedto the associated section at transformer Q connected at an intermediatepoint in the section as in Fig. 6 instead of at the exit end of thesection as in Fig. 7. Referring to the apparatus located at point C,when relay P is energized and relay K is energized, IOU-cycle current issupp ied to the primary 36 of transformer L over contact 33-83 of codingrelay K and front contact 65 of relay P in exactly the same manner as inFig. 7. lVhen relay P is ole-energized how ever, current flows fromsecondary 67 of transformer 0 through contact 3333 and back contact 66of relay P to primary 30 of transformer Q each time the contacts ofrelay K swing to the left. Under these conditions therefore the rails ofsection 3-6 are supplied at transformer Q with interrupted lO0-cyclecurrent in accordance with the caution code.

Referring now to Fig. 9, the apparatus here shown comprises two parallelstretches of railway track (Z and 6. Stretch e is divided into two tracksections G-H and HJ by means of insulated joints 2. The portion of track(Z which is opposite sections G H and H-J is insulated from the rest oftrack (Z by insulated joints 2 to form a track section E-F. Section GHis connected with section E F by means of a cross-over designlated'ingeneral by the reference character 9 connected with the sections bymeans of switches which are operated by means not shown in the drawingand'forming no part of the present disclosure. circuit controllerdesignated by the reference character WV? is controlled in accordancewith the positions of the switches whichconnect the crossover 9 with thetwo track sections. The position of the switches of crossover g forwhich the circuit controller is closed is indicated in the wiringdiagram by small letters inclosed by circles which are in turndesignated by the reference character lV For example, on the left-handside of the sheet close to relay Z are two contacts on circuitcontroller W The upper one of these contacts is indicated by a circleinclosing the letter R and the lower contact is indicated by a circlecontaining the letter N. The symbols mean that the lower or normalcontact N is closed when the switches of cross-over g are in theirnormal. positions, that is, when these switches are in such positionthat traffic can proceed without interference through section G-H. Whenthe switches of this cross over occupy their reverse positions, however,to permit traffic to move from section GH into section E-F over thecross-over g, the other or reverse contact designated by the referencecharacter R is closed.

In similar manner a cross-over it connects section E-F with section HJ,and the switches which connect this cross-over with the associatedsections control a circuit controller lV The contacts of this circuitcontroller are designated on the drawing by symbols similar to thosejust explained in connection with the circuit controller W It will benoticed that certain of the contacts of circuit controllers lV and 7 aremarked OR. This means that the contacts so designated are closed whenthe associated switches are in the reverse position, and remain closedwhen the switch moves away from the reverse position toward the normalposition until the switch is past the center or C position. In similarmanner contacts marked UN are closed when" the switch is in the centerposition, the normal position or any position between these two.

Current is at times supplied to the rails of each section of tracks cland e by means of a transformer designated by the reference character Twith an appropriate distinguishing exponent and having its secondary 3connected across the rails adjacent the exit end of the correspondingsection in series with the usual impedance 5. Current is at timessupplied to the primaries 4 of these trans formers by means which I willdescribe hereinafter. Each section is further provided with a trackrelay desi nated by the reference character R with an exponentcorresponding to the location and connected across the rails adjacentthe entrance end of each track section.

Traffic entering stretch d is governed by a traclrway signal TE andtraiiic entering stretch e is governed by a similar trackway signal r Asshown in the drawing each of iront contact 92 of relay these signals 'ris located adjacent the entrance end of the stretch of track which itgoverns, and comprises a semaphore arm capable of assuming threepositions to indicate proceec caution or stop, but this particularlocation and form are not essential to my invention; In actual practicethe signals 1 will usually be controlled manually from a remote pointsuch as an interlocking cabin so that they normally indicate stop butcan be caused to indicate caution or proceed when the operator in thecab wishes to permit traificto enter the stretch of track governed bythese signals. When a train moving in a direction in which the signalgoverns passes the signal, the indication of the signal immediatelychanges to a stop indication. Associated with each of the trackwaysignals 1' is a circuit controller designated by the reference characterU with an exponent corresponding to the associated signal and arrangedto be closed only when the correspondlng signal lndlcates proceed.

Associated with each track relay It is a stick relay designated by thereference character Z with a distinguishing exponent. Referringparticularly to stick relay Z this relay is provided with a pick-upcircuit which may be traced from terminal a, through back contact 94 oftrack relay R wires 95 and 96, circuit controller U controlled by signalr9, wires 97 and 98, winding of relay Z and wire 99 to terminal 7). Thiscircuit is closed only if relay R becomes deenergized when signal rindicates proceed. But if the deenergization of relay iresults from theentrance of a train into section G-l-l, signal 9- goes to stop as soonas the train passes the signal, thereby openlng circult controller U andinterrupting the pick-up circuit just traced. The relay Z having oncebeen picked up, is maintained in its energized condition over a stickcircuit which passes from terminal a, through back contact 94: of relayK wires 95 and 100, front contact 101 of relav 23 wires 102 and 98,winding of relay Z and wire 99 to terminal 6. Relay Z having once beenenergized, therefore, is maintained in its energized condition as longas ren y R remains ole-energized.

Stick relay'Z is provided with one pickup circuit which may be tracedfrom terminal a, through back contact 83 of relay R wires 83 and 84,circuit controller U wires 85 and 86, winding of relay Z and wire 87 toterminal 3). There ay is also provided with a second pick-up circuitwhich may be traced from terminal a, through a reverse contact oncircuit controller l t wire 91, Z wires 93, 9-0 and 80, winding of relayZ and wire 8? back to terminal 5. Relay Z theretore'bccoines ener gizedif a train enters section E-l with si nal 7 at )IOCGGCl or if rela Zbecomes l energized, as by the entrance of a train into section GH, whenthe switches of crossover 9 are reversed to permit this train to runinto section EF. Having once been energized, relay Z is maintained inits ener-' gized condition as long as relay R is deenergized, by virtueof a stick circuit which front contact 106 of relay Z wires. 10?, 108,and 109, winding of relay Z and wire 110 back to terminal ,6 therebypicking up relay Z Similarly, if

a-train enters section HJ from section Gl-l with the switches ofcross-over g in their nounal positions and relay Z energized, thede-energization of relay R completes a circuit from terminal a, throughback contact 103 of relay R wires 10 1 and 111, a normal contact oncircuit controller W wire 112, front contact 113 of relay Z wires 11%,108 and 109, winding of relay Z and wire to terminal 6. Having once beenenergized over either of the pickup circuits just traced, relay .Z issubsequently held in its energized condition as long as relay 3 Rremains re-energized, current then flowing from terminal a, through backcontact 103 of track relay-R wires 104-, 111, and 115; front contact 116of relay Z wires 116 and 109, winding of relay 7 and wire 110 toterminal b.

Associated with each stick relay Z is a coding relay K arranged to beenergized when the front contact 117 of the corresponding stick relay isclosed. Each of the coding relays ,K is constructed as explained inconnection with the preceding figures.

As shown in the drawing, relays R and R are energized, the switches ofcrossovers gand h are in their normal positions and signals T and W areindicating stops. A cirsuit is therefore closed, from terminal a,through :Eront contact 118 of relay, R wire 119, a ON contact of circuitcontroller W wire 133, a"Gl T contact on circuit controller N wire 1520,contact 1414 of coding relay K wire 121, and primary 4 of tracktransformer T to terminal Z). Current. is therefore supplied to therails of section EF by transformer T Relay R is energizedso that relay Zis de-energized. The'circuit for coding relay K is open at front contact117 of relay Z so that the coding'relay is deenergized and contact 14l1dis continuously closed. It follows that the current supplied to thetrack rails of section under these conditions is uninterrupted. Thecircuit for transformer T may be traced from terminal a, throu h frontcontact 122 of relay R wire 123, a CN contact on circuit controller wire124, contact 1414" of coding relay K wire 125, and primary 4 oftransformer T to terminal I). The current thus supplied to the rails ofsection H-J energizes relay R so that relay Z is Clo-energized and relayK is also (lo-energized. Contact 1414 of this coding relay is thereforecontinously closed and the current supplied to the section HJ isuninterrupted. Another circuit is closed from terminal a, through frontcontact 122 of relay R wire 123, a CN contact on circuit controller wire126, a CN contact on circuit controller W' wire 12?, contact 1414 ofcoding relay K wires 128 and 129, front contact -30 of relay R wire 131,a CN contact on circuit controller l/V wire 132, and primary 4 oftransformer T back to terminal b. It will be seen that this circuit isclosed only when the switches for cross-overs g and 7a both occupy theirnormal positions and when relays R and are both energized. The currentthus supplied to section GH by transformer T energizes relay R Relay Zis therefore deenergizcd and coding relay K is also ole-energized.Contact 1414 of relay K is therefore continuously closed and the currentsupplied to the rails of section GH is uninterrupted.

I will now assume that signal TE is moved to the proceed position andthat a train moving from left to right passes along stretch (Z. Whenthis train enters section EF, relay becomes de-energized and a pick-upcircuit is closed for relay Z over circuit controller U therebyenergizing the relay Z The'closing of front contact 117 of this relayenergizes relay K so that contact 1414 of relay K is operatedintermittently. The circuit for primary 4 of transformer T is thereforeperiodically interrupted so that current is supplied to section EF inaccordance with the proceed code. The signal 1 moves to the'stopindication as soon as the train ente rs the section but relay Z is nowheld on ergized over its stick circuit so that the pro ceed code issupplied to the train as it moves through the section. VJhen the trainleaves section EF relay R picks up, breaking the stick circuit for relayZ and de-energizi-Irg this relay. Relay K therefore becomes deenergizedand the interruptions in the current supplied to section EF cease. Withthe train in the section to the right of point F, relay R is deenergizedso that current flows from terminal a, through back contact 118 of relayR Wire 134, a CN contact on circuit controller VV wire 135, a CN contacton circuit controller WV wire 136, contact 14 14" of relay K wire 121,and primary 4 of transformer T to terminal 6. If, now, a

second train enterssection EF, passing sig nalr at proceed, relay isagain picked up and held up over its stick circuit after signal TE isreturned to its stop indication. The energization of relay K resultingfrom the closing of Contact 11'? relay Z causes contact 1414 to operateintermittently so that the circuit ust traced for primary 4 oftransformer T is periodically interrupted and current is then suppliedto section E-F in accordance with the caution code.

I will now assume that the switches of crossover hare reversed so thattraliic is permitted to move from section E". .1 into section HJ. All Rcontacts and CR contacts on circuit controller W are therefore closedand all N contacts and CH contacts are open. Current now flows fromterminal a, through a CR contact on circuit controller W' wires 13"? and136, contact 1414 of relay K wire 121, and primary 4 of transformer Tback to terminal 7). Current is also supplied to transformer T over acircuit which may be traced from terminal a through a CR contact oncircuit controller Vi wires 139, 140 ano 141, contact 1414 of relay Kwire 125, and primary 4 of transformer T to terminal 5. If new a trainenters section El?, passing signal WE at proceed, relay becomesenergized as before and relay K operates to interrupt the supply ofcurrent to the primary 4 of transformer T in accordance with the cautioncode. The train is therefore supplied with a caution code fromtransformer T as far as the cross-over it. The energizution of relay Zcompleted at front contact 106 a pick-up circuit for relay Z so that this relay is energized, thereby completing the operating circuit for relayK When the train proceeds over the cross-over h, entering section H al,and shunts relay R the closing of the back contact 108 of relay Rcompletes the stick circuit for relay Z so that the coding relay Kcontinues to operate until the train passes out of section H J. Theoperation of the relay K interrupts the current supplied to transformerT in accordance with the caution code. It follows that when the switchesof cross-over 7e are reversed to permit movements from point E to pointJ, a caution indication is received on board a train passing along thisroute irrespective of the condition of the track relays connected withthe rails to the right ofpoints F and J.

I will next assume all the switches are normal, that relays R and R areenergized, that signal r indicates proceed, and that a train moving inthe direction of the arrow passes this signal moving along the track 6.The de-energization of relay R completes the pick-up circuit for relay Zwhich thereupon becomes energized and completes the stick circuit forthis relay over its own front contact 101 and back contact 94 of relay RThe closing of front contact 117 of relay Z ener-

